This invention relates generally to new and improved telephone network interface apparatus for providing interconnections between a plurality of incoming telephone lines and a plurality of subscriber premises lines and for providing demarcation points therebetween to facilitate determination of whether a fault exists on an incoming telephone line or an associated subscriber premises line. It being understood by those skilled in the art that, since the deregulation of the telephone industry and divestiture of portions of the Bell System, such demarcation points are now mandated.
As is known to those skilled in the art, such telephone network interface apparatus are typically installed or mounted on a support surface such as a wall, or the like, by personnel typically referred to as construction and engineering personnel who also install or attach to the telephone network interface apparatus a typically large and heavy telephone network cable including a large number of incoming telephone lines or pairs, for example, a 50 line or pair cable, a 100 line or pair cable, a 200 line or pair cable, etc. As is further known, such construction or engineering personnel also typically perform a work task generally referred to in the art as "cable splicing" wherein a certain number of the incoming telephone lines or pairs included in the telephone network cable are separated or "spliced out" or "dropped off" at the telephone network interface apparatus. Such work tasks performed by the construction and engineering personnel are generally considered to be heavy duty work tasks and construction and engineering personnel tend to be rugged individuals or personnel. Thereafter, typically and as is further known to those skilled in the art, personnel typically referred to as installation and maintenance personnel perform the work tasks of interconnecting the "spliced out" or "dropped off" incoming telephone lines or pairs to telephone terminals, interconnecting small and light individual telephone wires or pairs between the telephone terminals and a plurality of subscriber terminals, and interconnecting the small and light individual subscriber premises lines or pairs to the subscriber terminals. Such work tasks performed by the maintenance and installation personnel are generally considered to be light duty work tasks and maintenance and installation personnel tend to be of the less rugged individuals or personnel. Accordingly, it has been found that it is undesirable to permit the more rugged construction and engineering personnel to have access to, typically, the telephone terminals, subscriber terminals, subscriber premises lines or pairs and the smaller wires providing interconnections therebetween. Thus, there exists a need in the art for telephone network interface apparatus which compartmentalizes or physically separates the portion of the telephone network interface apparatus to which the more rugged construction engineering personnel must have access to perform their heavy duty work tasks and which compartmentalizes or physically separates the portion of the telephone network interface apparatus to which the less rugged installation and maintenance personnel must have access to perform their relatively light duty work tasks, so as to deny the construction and engineering personnel access to the telephone terminals, subscriber terminals, subscriber premises lines or pairs, and their interconnecting wires to prevent them from unintentionally or inadvertently damaging the telephone terminals, subscriber terminals, subscriber premises lines or pairs, and their interconnecting wires.
As is further known to those skilled in the art, fire is of concern with telephone network interface apparatus and fire typically enters such apparatus along the incoming telephone network cable. Accordingly, there exists a further need for such compartmentalization for the sake of fireproofing or fire retarding the portion of the telephone network interface apparatus receiving subscriber premises terminals from one portion receiving the incoming telephone network cable.
Further, as known to those skilled in the art, due to considerations of cost and maximum applicability to the largest number of subscriber installations possible for a single telephone network interface apparatus such telephone network interface apparatus are limited to the number of incoming telephone lines and subscriber premises lines which may be handled by any specific telephone network interface apparatus. In spite of this limitation, as is further known, there exists some subscriber premises installation applications which require the service of a larger number of incoming telephone lines and subscriber premises lines than the specific network interface apparatus can handle. Accordingly, to avoid the cost of providing larger and more costly telephone network interface apparatus of greater line handling capacity but of limited application, there exists a need in the art for telephone network interface apparatus, a plurality of which may be installed adjacent to each other at a single subscriber premise and which different apparatus may be interconnected with different incoming telephone lines of a single large telephone network cable of the large number of lines or pairs noted above.
As is further known to those skilled in the art, prior art telephone network interface apparatus exist which include individual, replaceable, subscriber line interface modules which, upon the occurrence of a non-function in a single component of the module, permits such modules to be replaced or discarded on an individual module basis thereby avoiding the cost of discarding a larger portion of a telephone network interface apparatus, if not the entire apparatus itself.
Accordingly, it has been found that there exists a need in the telephone network interface apparatus art for new and improved telephone network interface apparatus which provides, in combination, the above-noted compartmentalization between the portions of the telephone network interface apparatus to which the construction engineering personnel must have access and the portions of the telephone network interface apparatus to which the installation and maintenance personnel must have access, and a plurality of which telephone network interface apparatus may be mounted adjacent each other for interconnection with different incoming telephone lines of a telephone network cable including a large number of incoming telephone lines, and which telephone network interface apparatus includes a plurality of the above-noted individual, replaceable, subscriber line interface modules.